Pass MetricsServiceClient into MetricsService, and create a simple stubbed TestMetricsServiceClient…

components/metrics/test_metrics_service_client.cc

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "components/metrics/test_metrics_service_client.h"
+
+namespace metrics {
+
+TestMetricsServiceClient::TestMetricsServiceClient() {
+}
+
+TestMetricsServiceClient::~TestMetricsServiceClient() {
+}
+
+void TestMetricsServiceClient::SetClientID(const std::string& client_id) {
+  client_id_ = client_id;
+}
+
+bool TestMetricsServiceClient::IsOffTheRecordSessionActive() {
+  return false;
+}
+
+std::string TestMetricsServiceClient::GetApplicationLocale() {
+  return "en-US";
+}
+
+bool TestMetricsServiceClient::GetBrand(std::string* brand_code) {
+  *brand_code = "BRAND_CODE";
+  return true;
+}
+
+SystemProfileProto::Channel TestMetricsServiceClient::GetChannel() {
+  return SystemProfileProto::CHANNEL_BETA;
+}
+
+std::string TestMetricsServiceClient::GetVersionString() {
+  return "5.0.322.0-64-devel";
+}
+
+}  // namespace metrics